In general, ingestible cameras (or “swallowable pill” cameras) are medical imaging devices that can be used to acquire high-resolution images within all portions of the gastrointestinal (GI) tract of an individual from mouth to anus. In general, conventional ingestible cameras are configured for imaging at wavelengths within the portion of the electromagnetic spectrum from visible to Near-Infrared (Near-IR) (about 400 nm to about 900 nm). These conventional ingestible cameras require an internal source of light to illuminate the interior lumen region of the GI tract. In some conventional ingestible pill designs, light emitting diodes (or other light sources) are used to provide the illumination that is needed for the imager detectors to acquire an image. In other words, conventional ingestible cameras utilize imaging schemes based on reflective light, wherein an external light source must shine light on a surface of the tissue of the GI tract to be imaged, and wherein an image is captured by detecting light that is reflected off the tissue surface being imaged. While these conventional ingestible cameras that use reflective light are sufficient to capture images of certain conditions (e.g., polyps on inner colon wall) that are exposed on the tissue surface of the GI tract, such cameras cannot be used to capture images or otherwise detect conditions that may exist within the GI tract tissue below the surface of the tissue.